The invention relates to a crimping tool for crimping crimp contacts, in particular crimp contacts which are supplied to the crimping tool in the form of a strip, with a pressing device and a feed device for advancing the crimp contacts to the pressing device, the feed device comprising an advancing element and means for reciprocating the advancing element.
Crimping tools of the described type have been known from practice for a long time, and they exist in a large variety of designs. The known crimping tools are designed and constructed for a streamlined processing of crimp contacts in the form of a strip, in a longitudinal or transverse movement, or for sortable individual contacts. Frequently, the known crimping tools are designed and constructed as quick-change tools, and they can be used in individual workstations or fully automatic machines and transfer lines. In this connection, it is possible to handle electric conductors with a cross sectional area from about 0.08 mm2 to 50 mm2.
A crimping tool of the initially described type is known, for example, from DE 197 50 770 A1. The known crimping tool comprises a feed device with an advancing element, which advances the crimp contacts, via a feed finger arranged on the advancing element, to the pressing device and in particular to a crimping stamp of the pressing device. With respect to a stable and precise crimping, it is necessary that the crimp contacts be fed exactly and reliably to the pressing device in alignment with the position of the crimping stamp. To this end, the feed device includes means for reciprocating the advancing element. The means comprise a pneumatic drive, which includes two piston rods in alignment and in contact with each other, or even made in one piece. The piston rods are adapted for movement relative to a common cylinder, which is formed in the advancing element. During a normal reciprocation of the advancing element, the piston rods remain stationary, whereas the advancing element moves along with the cylinder. Each of the piston rods accommodates a channel for suppliable compressed air, which extends from the exterior of the crimping tool into the cylinder.
The known crimping tool is problematic in that the cylinder bottom surface, which is decisive for the force transmission of the cylinder-piston arrangement, is clearly limited by the presence of the piston rod. This results in that, frequently, the force transmission and, thus, the advancing step do not suffice to pull down the contacts from a spool holding a strip of crimp contacts and over a safety brake with the required safety or required safety reserve. This may result in a faulty supply of crimp contacts to the pressing device, which in turn results in imperfect crimp connections.
It is therefore an object of the present invention to describe a crimping tool of the initially described type, which permits with constructionally simple means a reliable supply of crimp contacts to the pressing device.
The above and other objects and advantages of the invention are achieved by the provision of a crimping tool which comprises a pressing device which is mounted to a base body, and a feed device which includes an advancing element which is mounted for reciprocation so as to advance the strip of crimp contacts. Means are provided for reciprocating the advancing element which include two cylinder-piston arrangements, which are independent of each other.
In a way according to the invention, it has been recognized that the foregoing object is achieved in a surprisingly simple manner by providing two cylinder-piston arrangements, which are independent of each other. To this end, a separate cylinder is associated with each cylinder-piston arrangement. This in turn results in the advantage that the bottom surface of the cylinder, which is decisive for the force transmission, is not limited in its size by any components. Thus, with an ultimately identically dimensioned construction of a system for supplying a flowable medium to the cylinder-piston arrangements, it is possible to produce a substantially greater pushing force for the advancing element.
Consequently, the crimping tool of the present invention realizes a crimping tool, which permits with constructionally simple means a reliable supply of crimp contacts to the pressing device.
As regards a reliable guidance of the advancing element during its reciprocation, it would be possible to guide the advancing element by the two cylinder-piston arrangements at the same time. This would prevent the advancing element from tilting relative to the pressing device.
A particularly stable movement of the advancing element could be ensured by arranging the main axes of the cylinder-piston arrangements along a line, thereby avoiding tilting moments of the advancing element relative to the feed device and the pressing device. The main axis of the cylinder-piston arrangement extends in the center and in the longitudinal direction of the piston and the cylinder.
To realize a particularly compact crimping tool or a particularly compact feed device, it would be possible to arrange the main axes of the cylinder-piston arrangements in offset relationship with each other. In such a realization, the cylinder-piston arrangements could extend in part parallel to each other.
In particular, in the case of an offset placement of the cylinder-piston arrangements, it would be possible to place one of the cylinder-piston arrangements in the lower portion and the other cylinder-piston arrangement in the upper portion of the advancing element. With that, the cylinder-piston arrangements could quasi overlie each other.
The pistons of the cylinder-piston arrangements could include piston rods. In this instance, the advancing element would be guided on the pistons or piston rods. In a corresponding manner, it would be possible to arrange the cylinders of the cylinder-piston arrangements in the advancing element. In this connection, it is possible to realize the cylinders as cutouts in the advancing element.
The reciprocation of the advancing element could require different pushing forces. In particular, the movement of the advancing element in the direction toward the pressing device, which ensures the feed of the crimping contacts, could require a greater pushing force than the movement in the direction away from the pressing device. In a corresponding manner, the cylinder-piston arrangement for moving the advancing element in the direction toward the pressing device, could have a larger diameter than the other cylinder-piston arrangement. This could show in the diameter of the piston and the cylinder.
As regards a particularly reliable guidance of the advancing element during its reciprocation, it would be possible to provide for the advancing element at least one guide element. In this connection, the guide element could be a rod extending through a passageway in the advancing element. According to requirements, the rod could basically be arranged between the two cylinder-piston arrangements. However, an arrangement above or below or laterally of the two cylinder-piston arrangements is also possible.
With respect to a particularly compact construction of the crimping tool, the guide element could perform a double function to the extent that it is designed and constructed on the one hand for guiding the advancing element, and on the other hand for supplying a flowable medium. To this end, the guide element or rod could be constructed with a channel or made tubular for purposes of supplying one cylinder-piston arrangement with a flowable medium. With that, it would be possible to supply one cylinder-piston arrangement or both cylinder piston arrangements with a flowable medium. As a flowable medium, it is preferred to use compressed air. However, other liquid or gaseous media are also possible, such as for example oil.
To ensure a safe and reliable operation of the crimping tool, the supply of the cylinder-piston arrangements could be controllable with a flowable medium via a control unit. The control unit could include a valve system, which supplies the medium originating from a source to the cylinder-piston arrangements in a suitable manner.
In a particularly practical manner, the pistons or the piston rods could be made tubular for purposes of directing a flowable medium into the respective cylinder.
In a particularly practical manner, it would be possible to couple the control unit with the pressing device in a functional manner. This means that the control unit and thus the movement of the advancing element are controlled in accordance with the working position of the pressing device. As a result, the operation of the pressing device is coupled with the supply operation for the crimping contacts. The coupling could occur via the movement of the crimping stamp associated with the pressing device, which controls by its movement the control unit via a cam.